inorganic - acids, alkalis, titrations

	acid colour	basic/alkali colour
litmus
phenolphthalein
methyl orange

why is litmus not good for titrations

colour change is not sharp (goes through a purple transition colour) in neutral solutions making it

difficult to determine an endpoint

ph scale acidic → alkali

universal indicator colorus

weakly/strongly acidic/alkaline sections

what kind of indicator is needed for titration

sharp colour change

when acids are added to water, they form ______ charged _______ ions (^__). This presence makes a solution ______

when acids are added to water, they form positively charged hydrogen ions (H⁺). This presence makes a solution acidic

when alkalis are added to water, they form ______ charged _______ ions (^__). This presence makes a solution ______

• When alkalis are added to water, they form negative hydroxide ions (OH^–)

• The presence of the OH^– ions is what makes the aqueous solution an alkali

acids are p_____ ______

proton donors

alkalis are p______ _______

proton acceptors

what is a neutralization reaction

what reacts with what to produce what

A neutralisation reaction occurs when an acid reacts with an alkali

When these substances react together in a neutralisation reaction, the H⁺ ions react with the OH^– ions to produce water

neutralisation reaction hcl and naoh
- write out individual reactions taking place

titration equipment labelled

6 labels

+a pipette

acid + metal oxide →

acid + metal oxide → salt + water

acid + metal hydroxide →

acid + metal hydroxide → salt + water

acid + ammonia →

acid + ammonia → ammonium salt

titration steps

1. use pipette and pipette filler to add (25cm3) of ALKALI to a conical flask, with some drops of sharp-change indicator (e.g. phenolpthalein)

2. fill burette with acid

3. place conical flask on white tile so tip of burette is inside with flask

4. use burette to add acid to alkali a little at a time, swirling the conical flask. add the acid drop-wise near the end-point.

5. indicator changes colour when all alkali has been neutralised (e.g. phenolphtalein turns colourless)

6. record volume of acid - eye level with the meniscus, repeat multiple times

what is a rough titration

to estimate rough point at which neutralisation occurs

to reduce ______ don’t add ______ at the start after having done the titration a couple times before

to reduce contamination don’t add indicator at the start

the burette must be ____ to measure the volume of acid added

the burette must be GRADUATED to measure the volume of acid added